/* 屏幕宽度小于500px */
@media screen and (max-width: 500px) {
    a {
        text-decoration: none;
        color: white;
        line-height: 90px;
        font-size: 20px;
        margin-right: 40px;
    }

    nav {
        width: 300px;
    }

    img {
        width: 120px;
    }

    .iconDrawer {
        display: block;
        height: 50px;
        line-height: 50px;
        font-size: 42px;
        color: #ffffff;
        width: 40px;
        position: absolute;
        top: 18px;
        left: 30px;
        transform: scale(1.4);

        /* 兼容 */
        -webkit-transition: font-size 0.25s linear,
            width 0.25s linear;
        -moz-transition: font-size 0.25s linear,
            width 0.25s linear;
        transition: font-size 0.25s linear,
            width 0.25s linear;
    }

    .iconDrawer:hover {
        color: #666;
    }

    img {
        transform: scale(1.5);
    }
}

/* 屏幕宽度大于500px */
@media screen and (min-width: 500px) {
    a {
        text-decoration: none;
        /* 清除a标签默认样式 */
    }

    .navItem {
        font-size: 24px;
        line-height: 80px;
        margin-right: 40px;
    }

    .navItem:hover {
        color: red;
    }

    nav {
        width: 1200px;
    }

    /* 清除浮动 */
    nav:after {
        content: ".";
        display: block;
        height: 0;
        visibility: hidden;
        clear: both;
    }

    .active {
        color: red;
    }

    .button {
        display: inline-block;
        color: #ffffff;
        background-color: #c00;
        border: none;
        height: 54px;
        width: 110px;
        border-radius: 25px;
        font-size: 18px;
        cursor: pointer;
        text-align: center;
        line-height: 3;
    }

    .button:hover {
        background-color: #f00;
        color: #fff;
    }
}